The invention relates to a milling machine operated in connection with a continuous casting machine, working horizontally, from which a number of strands in a stepwise or intermitten fashion. The milling machine is provided with cutting tools for milling the upper and lower surfaces of several parallel, elongated workpieces or strands drawn out of the continuous casting machine. A pair of feeding rolls are provided which engage one of the strands whereby the milling machine is displaceable with respect to the continuous casting machine and the feeding speed of the milling machine is controllable in dependence on the drawing speed of the continuous casting machine.
A milling machine of this type which is useable with a single strand has already been proposed in the German Patent No. 2,212,344 and in the corresponding U.S. Pat. No. 3,791,258. With such a machine, the feed rolls are driven at an average rate of the drawing speed, which is calculated from the waiting time between successive draws of the workpiece from the casting machine, the length of workpiece drawn during each drawing operation, and the drawing time of the continuous casting machine of the single strand of this machine respectively.
Frequently, however, there are two or more strands arranged side by side and drawn intermittently from a continuous casting machine. These strands are often drawn at different lengths and at different speeds. If two or more strands having different drawing speeds are milled by the above-mentioned milling machine, the milling process of only one strand can be provided in a favorable manner. The milling tool of the prior patent is able to work on the second and the further strands, but the drawing movement of one of these strands causes a stress on that part of the milling tool during the drawing movement. When, and because, the additional strands have different drawing lengths and speeds than the first strand, the smooth surfaces of these second and further strands are destroyed by the resulting stresses and the service life of the tool which works on these strands is reduced.
It is the object of the invention to provide a milling machine of the above mentioned kind for milling two or more strands cast side by side having different drawing speeds and different drawing lengths that produces good surfaces and maintains long tool service life.